The present disclosure relates to a quinone derivative and an electrophotographic photosensitive member.
Electrophotographic photosensitive members are formed from various materials and usable in image forming apparatuses (for example, copiers, facsimile machines, and laser printers) employing the Carlson process. Examples of such electrophotographic photosensitive members include inorganic photosensitive members in which an inorganic material (for example, amorphous silicon) is used for a photosensitive layer thereof and organic photosensitive members (organic photoconductors: OPCs) in which an organic material is used for a photosensitive layer thereof. Organic photosensitive members have many advantages such as being inexpensive, highly producible, and environmentally-clean compared to inorganic photosensitive members. Therefore, there has been extensive research on organic photosensitive members.
Examples of organic photosensitive members include a so-called function separation type photosensitive member, that is, a multi-layer photosensitive member in which a charge generating layer and a charge transport layer are stacked on one another, and a single-layer photosensitive member in which a charge generating material and a charge transport material are dispersed in a single photosensitive layer.
Charge transport materials that are used in such photosensitive members are required to have high carrier mobility. Most charge transport materials having high carrier mobility are hole transport materials. Therefore, organic photosensitive members that, for the sake of mechanical strength, have a charge transport layer as an outermost layer are in practical use are limited to negatively chargeable multi-layer organic photosensitive members. However, negatively chargeable organic photosensitive members use negative corona discharge and therefore generate a large amount of ozone, causing a problem such as pollution of the environment and deterioration of the photosensitive members.
In order to overcome such a disadvantage, use of an electron transport material as a charge transport material has been considered.